'\" te
.\"  Copyright 1989 AT&T
.\" Copyright (C) 2008, Sun Microsystems, Inc. All Rights Reserved
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.  See the License for the specific language governing permissions and limitations under the License.
.\" When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE.  If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
.TH RLOGIN 1 "September 12, 2020"
.SH NAME
rlogin \- remote login
.SH SYNOPSIS
.nf
\fBrlogin\fR [\fB-8EL\fR] [\fB-e\fIc\fR\fR ] [\fB-A\fR] [\fB-K\fR] [\fB-x\fR] [\fB-PN\fR | \fB-PO\fR] [\fB-f\fR | \fB-F\fR] [\fB-a\fR]
     [\fB-l\fR \fIusername\fR] [\fB-k\fR \fIrealm\fR] \fIhostname\fR
.fi

.SH DESCRIPTION
The \fBrlogin\fR utility establishes a remote login session from your terminal
to the remote machine named \fIhostname\fR. The user can choose to kerberize
the rlogin session using Kerberos V5 and also protect the data being
transferred.
.sp
.LP
Hostnames are listed in the \fIhosts\fR database, which can be contained in the
\fB/etc/hosts\fR file, the Network Information Service (\fBNIS\fR) \fBhosts\fR
map, the Internet domain name server, or a combination of these. Each host has
one official name (the first name in the database entry), and optionally one or
more nicknames. Either official hostnames or nicknames can be specified in
\fIhostname\fR.
.sp
.LP
The user can opt for a secure rlogin session which uses Kerberos V5 for
authentication. Encryption of the session data is also possible. The rlogin
session can be kerberized using any of the following Kerberos specific options:
\fB-A\fR, \fB-PN\fR or \fB-PO\fR, \fB-x\fR, \fB-f\fR or \fB-F\fR, and \fB-k\fR
\fIrealm\fR. Some of these options (\fB-A\fR, \fB-x\fR, \fB-PN\fR or \fB-PO\fR,
and \fB-f\fR or \fB-F\fR) can also be specified in the \fB[appdefaults]\fR
section of \fBkrb5.conf\fR(5). The usage of these options and the expected
behavior is discussed in the OPTIONS section below. If Kerberos authentication
is used, authorization to the account is controlled through rules in
\fBkrb5_auth_rules\fR(7). If this authorization fails, fallback to normal
\fBrlogin\fR using \fBrhosts\fR occurs only if the \fB-PO\fR option is used
explicitly on the command line or is specified in \fBkrb5.conf\fR(5). Also
notice that the \fB-PN\fR or \fB-PO\fR, \fB-x\fR, \fB-f\fR or \fB-F\fR, and
\fB-k\fR \fIrealm\fR options are just supersets of the \fB-A\fR option.
.sp
.LP
The remote terminal type is the same as your local terminal type, as given in
your environment \fBTERM\fR variable. The terminal or window size is also
copied to the remote system if the server supports the option. Changes in size
are reflected as well. All echoing takes place at the remote site, so that
(except for delays) the remote login is transparent. Flow control using
Control-S and Control-Q and flushing of input and output on interrupts are
handled properly.
.SH OPTIONS
The following options are supported:
.sp
.ne 2
.na
\fB\fB-8\fR\fR
.ad
.RS 15n
Passes eight-bit data across the net instead of seven-bit data.
.RE

.sp
.ne 2
.na
\fB\fB-a\fR\fR
.ad
.RS 15n
Forces the remote machine to ask for a password by sending a null local
username.
.RE

.sp
.ne 2
.na
\fB\fB-A\fR\fR
.ad
.RS 15n
Explicitly enables Kerberos authentication and trusts the \fB\&.k5login\fR file
for access-control. If the authorization check by \fBin.rlogind\fR(8) on the
server-side succeeds and if the \fB\&.k5login\fR file permits access, the user
is allowed to login without supplying a password.
.RE

.sp
.ne 2
.na
\fB\fB-e\fR\fIc\fR\fR
.ad
.RS 15n
Specifies a different escape character, \fIc\fR, for the line used to
disconnect from the remote host.
.RE

.sp
.ne 2
.na
\fB\fB-E\fR\fR
.ad
.RS 15n
Stops any character from being recognized as an escape character.
.RE

.sp
.ne 2
.na
\fB\fB-f\fR\fR
.ad
.RS 15n
Forwards a copy of the local credentials (Kerberos Ticket Granting Ticket) to
the remote system. This is a non-forwardable ticket granting ticket. You must
forward a ticket granting ticket if you need to authenticate yourself to other
Kerberized network services on the remote host. An example is if your home
directory on the remote host is \fBNFS\fR mounted via Kerberos V5. If your
local credentials are not forwarded in this case, you can not access your home
directory. This option is mutually exclusive with the \fB-F\fR option.
.RE

.sp
.ne 2
.na
\fB\fB-F\fR\fR
.ad
.RS 15n
Forwards a forwardable copy of the local credentials (Kerberos Ticket Granting
Ticket) to the remote system. The \fB-F\fR option provides a superset of the
functionality offered by the \fB-f\fR option. For example, with the \fB-f\fR
option, after you connected to the remote host, any attempt to invoke
\fB/usr/bin/ftp\fR, \fB/usr/bin/telnet\fR, \fB/usr/bin/rlogin\fR, or
\fB/usr/bin/rsh\fR with the \fB-f\fR or \fB-F\fR options would fail. Thus, you
would be unable to push your single network sign on trust beyond one system.
This option is mutually exclusive with the \fB-f\fR option.
.RE

.sp
.ne 2
.na
\fB\fB-k\fR \fIrealm\fR\fR
.ad
.RS 15n
Causes \fBrlogin\fR to obtain tickets for the remote host in \fIrealm\fR
instead of the remote host's realm as determined by \fBkrb5.conf\fR(5).
.RE

.sp
.ne 2
.na
\fB\fB-K\fR\fR
.ad
.RS 15n
This option explicitly disables Kerberos authentication. It can be used to
override the \fBautologin\fR variable in \fBkrb5.conf\fR(5).
.RE

.sp
.ne 2
.na
\fB\fB-l\fR \fIusername\fR\fR
.ad
.RS 15n
Specifies a different \fIusername\fR for the remote login. If you do not use
this option, the remote username used is the same as your local username.
.RE

.sp
.ne 2
.na
\fB\fB-L\fR\fR
.ad
.RS 15n
Allows the rlogin session to be run in "\fBlitout\fR" mode.
.RE

.sp
.ne 2
.na
\fB\fB-PN\fR\fR
.ad
.br
.na
\fB\fB-PO\fR\fR
.ad
.RS 15n
Explicitly requests the new (\fB-PN\fR) or old (\fB-PO\fR) version of the
Kerberos `\fBrcmd\fR' protocol. The new protocol avoids many security problems
prevalent in the old one and is considered much more secure, but is not
interoperable with older (MIT/SEAM) servers. The new protocol is used by
default, unless explicitly specified using these options or by using
\fBkrb5.conf\fR(5). If Kerberos authorization fails when using the old
`\fBrcmd\fR' protocol, there is fallback to regular, non-kerberized
\fBrlogin\fR. This is not the case when the new, more secure `\fBrcmd\fR'
protocol is used.
.RE

.sp
.ne 2
.na
\fB\fB-x\fR\fR
.ad
.RS 15n
Turns on \fBDES\fR encryption for all data passed through the rlogin session.
This reduces response time and increases \fBCPU\fR utilization.
.RE

.SS "Escape Sequences"
Lines that you type which start with the tilde character (\fB~\fR) are "escape
sequences." The escape character can be changed using the \fB-e\fR option.
.sp
.ne 2
.na
\fB\fB~.\fR\fR
.ad
.RS 10n
Disconnects from the remote host. This is not the same as a logout, because the
local host breaks the connection with no warning to the remote end.
.RE

.sp
.ne 2
.na
\fB\fB~susp\fR\fR
.ad
.RS 10n
Suspends the login session, but only if you are using a shell with Job Control.
\fBsusp\fR is your "suspend" character, usually Control-Z. See \fBtty\fR(1).
.RE

.sp
.ne 2
.na
\fB\fB~dsusp\fR\fR
.ad
.RS 10n
Suspends the input half of the login, but output is still able to be seen (only
if you are using a shell with Job Control). \fBdsusp\fR is your "deferred
suspend" character, usually Control-Y. See \fBtty\fR(1).
.RE

.SH OPERANDS
.ne 2
.na
\fB\fIhostname\fR\fR
.ad
.RS 12n
The remote machine on which \fIrlogin\fR establishes the remote login session.
.RE

.SH USAGE
For the kerberized rlogin session, each user can have a private authorization
list in a file, \fB\&.k5login\fR, in his home directory. Each line in this file
should contain a Kerberos principal name of the form
\fIprincipal\fR/\fIinstance@realm\fR. If there is a \fB~/.k5login\fR file,
access is granted to the account if and only if the originating user is
authenticated to one of the principals named in the \fB~/.k5login\fR file.
Otherwise, the originating user is granted access to the account if and only if
the authenticated principal name of the user can be mapped to the local account
name using the \fIauthenticated-principal-name\fR \(-> \fIlocal-user-name\fR
mapping rules. The \fB\&.k5login\fR file (for access control) comes into play
only when Kerberos authentication is being done.
.sp
.LP
For the non-secure rlogin session, each remote machine can have a file named
\fB/etc/hosts.equiv\fR containing a list of trusted host names with which it
shares user names. Users with the same user name on both the local and remote
machine can \fBrlogin\fR from the machines listed in the remote machine's
\fB/etc/hosts.equiv\fR file without supplying a password. Individual users
may set up a similar private equivalence list with the file \fB\&.rhosts\fR
in their home directories. Each line in this file contains two names, that is,
a host name and a user name, separated by a space. An entry in a remote user's
\fB\&.rhosts\fR file permits the user named \fIusername\fR who is logged into
\fIhostname\fR to log in to the remote machine as the remote user without
supplying a password. If the name of the local host is not found in the
\fB/etc/hosts.equiv\fR file on the remote machine, and the local user name and
host name are not found in the remote user's .\fBrhosts\fR file, then the
remote machine prompts for a password. Host names listed in the
\fB/etc/hosts.equiv\fR and \fB\&.rhosts\fR files must be the official host
names listed in the \fBhosts\fR database. Nicknames can not be used in either
of these files.
.sp
.LP
For security reasons, the \fB\&.rhosts\fR file must be owned by either the
remote user or by root.
.SH FILES
.ne 2
.na
\fB\fB/etc/passwd\fR\fR
.ad
.RS 23n
Contains information about users' accounts.
.RE

.sp
.ne 2
.na
\fB\fB/usr/hosts/*\fR\fR
.ad
.RS 23n
For \fIhostname\fR version of the command.
.RE

.sp
.ne 2
.na
\fB\fB/etc/hosts.equiv\fR\fR
.ad
.RS 23n
List of trusted hostnames with shared user names.
.RE

.sp
.ne 2
.na
\fB\fB/etc/nologin\fR\fR
.ad
.RS 23n
Message displayed to users attempting to login during machine shutdown.
.RE

.sp
.ne 2
.na
\fB\fB$HOME/.rhosts\fR\fR
.ad
.RS 23n
Private list of trusted hostname/username combinations.
.RE

.sp
.ne 2
.na
\fB\fB$HOME/.k5login\fR\fR
.ad
.RS 23n
File containing Kerberos principals that are allowed access.
.RE

.sp
.ne 2
.na
\fB\fB/etc/krb5/krb5.conf\fR\fR
.ad
.RS 23n
Kerberos configuration file.
.RE

.sp
.ne 2
.na
\fB\fB/etc/hosts\fR\fR
.ad
.RS 23n
Hosts database.
.RE

.SH SEE ALSO
.BR rsh (1),
.BR stty (1),
.BR tty (1),
.BR hosts (5),
.BR hosts.equiv (5),
.BR krb5.conf (5),
.BR nologin (5),
.BR attributes (7),
.BR krb5_auth_rules (7),
.BR in.rlogind (8)
.SH DIAGNOSTICS
The following message indicates that the machine is in the process of being
shut down and logins have been disabled:
.sp
.in +2
.nf
NO LOGINS: System going down in \fIN\fR \fBminutes\fR
.fi
.in -2
.sp

.SH NOTES
When a system is listed in \fBhosts.equiv\fR, its security must be as good as
local security. One insecure system listed in \fBhosts.equiv\fR can compromise
the security of the entire system.
.sp
.LP
The Network Information Service (\fBNIS\fR) was formerly known as Sun Yellow
Pages (\fBYP\fR.) The functionality of the two remains the same. Only the name
has changed.
.sp
.LP
This implementation can only use the \fBTCP\fR network service.
